What type of data is specifically designed to present possible erroneous conditions?

The correct answer is erroneous data, as this type of data is explicitly created to test how a system behaves under conditions that are expected to cause errors or failures. Erroneous data is essential in software testing because it helps developers identify weaknesses or bugs in their code by simulating unexpected input that the application might encounter in real-world scenarios. It is used to ensure that the system handles these edge cases gracefully, without crashing or producing incorrect results.

Other types of data mentioned have distinct purposes. Test data refers to a broader category of inputs used during the testing phase, including valid inputs, while extreme data focuses on inputs that are significantly outside normal operating conditions but are not necessarily erroneous. Boundary data specifically looks at the limits of input ranges, such as the maximum and minimum values acceptable for a given input. While these other categories are useful in their own rights, they do not specifically target the testing of erroneous conditions like erroneous data does.